Digital Signage Trends: LED Backlights

By James Wood

The description of digital signage might compete with the military for the EUA award (Excessive Use of Acronyms). You can look at getting an LCD with HDMI and DVI input so the PC content is in HD. Add to the list CCFL and LED when referring to the way the screen is lit. Since liquid crystal displays (LCDs) don’t produce any light, they need to be lit from behind. The old standard has been to use cold compact florescent lights (CCFL) because it produces a uniform light across the whole screen for an affordable price.

But light emitting diodes (LEDs) have improved to the point where they are taking over for the CCFLs. The Planar ep46L and ep55L are leading the way with bright, efficient LED lighted LCD displays. They are 46 and 55 inches in diagonal respectively. Chris Connery, of DisplaySearch, reflected on his time at InfoComm 2011. He points out that LED backlights are a growing trend in digital signage because they are bright, efficient and long-lasting.

The Planar EP-Series displays are perfect examples of where the industry is going. They shine with 450 candela per square meter, which is about twice the brightness of a typical LCD monitor and on par with home theater displays. But to keep the brightness under control there’s a built in sensor that can adjust the brightness of the backlight to match the ambient light, automatically. Electricity usage drops by 30 to 50 percent when using an LED backlight versus the CCFLs. In addition, there’s no mercury used in producing the LEDs while the CCFLs won’t function without it. And LEDs last for years – the EP-Series can run, 24/7 for nearly six years before the LEDs wear out (and that’s only dropping to half-brightness, not burning out altogether).